Light Emitting Diodes (LEDs) have been used in many applications to replace conventional incandescent lamps, fluorescent lamps, neon tube and fiber optics light sources in order to reduce costs and to increase reliability. Due to the fact that LEDs consume less electrical energy than most conventional light sources, while exhibiting much longer lifetime, many designs could be made for various applications, such as traffic signal lights, channel letters, conventional illuminated commercial signs, street name signs, and street lights.
In the case of street lights, parking lot lights and area illumination lights, most existing products utilize HID lamps as their respective light source. Cobrahead luminaires and shoebox luminaires are two frequently used outdoor luminaires for such applications. A cross section schematic drawing of a conventional cobrahead luminaire is provided in FIG. 1a. As illustrated, such a cobrahead luminaire comprises a lamp 100, a lens 110, incoming AC lines 120, a cobra housing 130, a reflector 140, and a lamp socket 150. In FIG. 1b, a cross section schematic drawing of a conventional shoebox luminaire is also provided. As illustrated, such a shoebox luminaire comprises a lamp 200, a lens 210, incoming AC lines 220, a shoebox housing 230, a reflector 240, and a lamp socket 250.
Major disadvantages of using these lamps, however, are 1) they need to be replaced often due to the shorter lifespan of the lamp; 2) part of the light from the HID lamp is wasted because it is aimed in directions not useful to the original lighting purpose; 3) some of them contain hazardous material; and 4) they exhibit a non-favorable spectrum at night. It is therefore desirable to replace existing HID lamps with long-lasting LED products.
Current LED retrofitting mechanisms are also limited. For example, current retrofitting methods require LED light engines to be screwed onto their respective housings. However, physical constraints of the housing sometimes do not allow for LED light engines to fully rotate. It is therefore desirable to also develop a retrofitting method wherein the LED light engine does not need to be fully rotated.